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Tankless or Indirect Fired Water Heater?

I buying a new oil boiler and trying to determine whether an indirect fired water heater really saves on fuel and how much.

Currently I have a very old tankless unit. We have a family of four and we have been satisifed with the amount of hot water we get out of it. So, the only reason to get an indirect fired water heater would be to save on oil.

On the one hand, it would seem to me (a rank amateur) that a tankless unit might burn less fuel. In the winter, obviously, the boiler is hot anyway. In the summer, the boiler will have to stay hot, but the indirect fired tank would need to stay hot too.

On the other hand, I spoke to Weil Mclain's customer service and they assure me that the indirect will use less oil, but they cannot give me any data to show that, nor can they give me any idea how much less oil it will use.

Can anyone give me a definitive answer why the indirect uses less oil and how much less oil it will use?

On the other hand, I spoke to Weil Mclain's customer service and they assure me that the indirect will use less oil, but they cannot give me any data to show that, nor can they give me any idea how much less oil it will use.

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tankless is a unit that usually hangs on a wall, has its own fire to heat the water and only fires on demand?

indirect is a stand alone storage tank, looks like a standard water heater, and is heater by an existing boiler. Some variations to this description are likely.

what fuel is the existing tankless unit, I did not realize they had oil fired tankless units?

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from an excerpt by Paul Jacob in Sun City, AZ

I buying a new oil boiler and trying to determine whether an indirect fired water heater really saves on fuel and how much.

Currently I have a very old tankless unit. We have a family of four and we have been satisifed with the amount of hot water we get out of it. So, the only reason to get an indirect fired water heater would be to save on oil.

On the one hand, it would seem to me (a rank amateur) that a tankless unit might burn less fuel. In the winter, obviously, the boiler is hot anyway. In the summer, the boiler will have to stay hot, but the indirect fired tank would need to stay hot too.

On the other hand, I spoke to Weil Mclain's customer service and they assure me that the indirect will use less oil, but they cannot give me any data to show that, nor can they give me any idea how much less oil it will use.

Can anyone give me a definitive answer why the indirect uses less oil and how much less oil it will use?

Like what you said, the system really gets its savings when you are heating your house, during summer months the furnace basically acts as a conventional tank water heater; so it isn't necessarily wasting any fuel but you won't be seeing any savings in the summer except the fact that the boiler is usually a higher efficiency and that is better than the standard tank water heater.

Unfortunately, I don't have any cold hard data of it compared to tankless, I guess some people just have to be the guinea pigs.

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Summer Design Temperature: 83 F Dry Bulb ~ 69 F Wet Bulb (California Climate Zone 7)

I buying a new oil boiler and trying to determine whether an indirect fired water heater really saves on fuel and how much.

Currently I have a very old tankless unit. We have a family of four and we have been satisifed with the amount of hot water we get out of it. So, the only reason to get an indirect fired water heater would be to save on oil.

On the one hand, it would seem to me (a rank amateur) that a tankless unit might burn less fuel. In the winter, obviously, the boiler is hot anyway. In the summer, the boiler will have to stay hot, but the indirect fired tank would need to stay hot too.

On the other hand, I spoke to Weil Mclain's customer service and they assure me that the indirect will use less oil, but they cannot give me any data to show that, nor can they give me any idea how much less oil it will use.

Can anyone give me a definitive answer why the indirect uses less oil and how much less oil it will use?

My indirect saved me about 200 gallons a year.

An indirect tank usally allows you to install a smaller boiler since you do not have to raise the water from 40 to 110 degrees immediately. I have a 2000 Sf colonial and make heat and hot water with a 77K input boiler and 40 gallon indirect.

Be sure you have a contractor that will perform and understands heat loss. Do not include the indirect for boiler sizing unless you have 3 or more bathrooms.

Indirect is the way to go. You do not have to maintain boiler temp and the indirect works like a thermos, loosing very little heat. I installed a Baisi triple pass boiler, that only fires during a call for heat or hot water, with a phase III indirect about seven years ago. I burn about 1/2 gallon a day during the cooling season and about 1-1/2 gallons a day during the heating season. It's heating a small three bedroom ranch on Long Island.

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Of they make the water maker the priority zone the size of the boiler is irrelevant. You must have a weil McLain gold with small water tank inside? Have you considered new, propane boiler and indirect water heater? Oil is evpensive.

Of they make the water maker the priority zone the size of the boiler is irrelevant. You must have a weil McLain gold with small water tank inside? Have you considered new, propane boiler and indirect water heater? Oil is evpensive.

This is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise here. Please apply to the AOPC today, thank you.

I may have used the wrong terminology -- by tankless, I mean a summer/winter hookup coil. I think some of you understood that.

Don't know what brand boiler I am doing yet. I have another post asking for recommendations. The proposals I have received have been for a Bryant BW4 or WeilMcLain WGO4. I have found it difficult to find good info to compare and contrast proposals, so all advice is welcomed.